Which sample contains a total of 6.0 × 10^{23} atoms?

• A. 1 mole of oxygen gas (O_2)
• B. 1 mole of sodium chloride (NaCl)
• C. 1 mole of helium (He)
• D. 1 mole of water (H_2O)

Answer: (C)

Verified step by step guidance

1. Recall that 1 mole of any substance contains Avogadro's number of particles, which is approximately \$6.0 \times 10^{23}$ entities (atoms, molecules, or formula units).
2. Identify the type of particles counted in each sample: for elemental gases like helium (He), the particles are atoms; for molecular substances like oxygen gas (O_2) and water (H_2O), the particles are molecules; for ionic compounds like sodium chloride (NaCl), the particles are formula units composed of ions.
3. Understand that the question asks for a sample containing \$6.0 \times 10^{23}$ atoms, not molecules or formula units. Therefore, you need to consider how many atoms are present in 1 mole of each substance.
4. Calculate the total number of atoms in 1 mole of each sample by multiplying the number of particles (1 mole = \$6.0 \times 10^{23}$ particles) by the number of atoms per particle: for He, 1 atom per particle; for O_2, 2 atoms per molecule; for NaCl, 2 atoms per formula unit; for H_2O, 3 atoms per molecule.
5. Compare the total atoms in each sample to \$6.0 \times 10^{23}\( atoms and identify which sample contains exactly that number of atoms. The sample with 1 mole of helium (He) contains exactly \)6.0 \times 10^{23}$ atoms because each particle is a single atom.